The schema.xml file that is created once you create your opensolr collection, comes with a field type called "spell" and a field defined called "spell".
Simply make sure that you have those two defined in your custom schema.xml and you should have spellcheck and terms suggestion enabled.

So, just make sure the following snippets are present in your schema.xml file:

1) The spell field type definition:

<fieldtype class="solr.TextField" name="spell" positionincrementgap="100">
  <analyzer type="index">
    <tokenizer class="solr.StandardTokenizerFactory">
    <filter class="solr.StopFilterFactory" ignorecase="true" words="stopwords.txt">
    <filter class="solr.StandardFilterFactory">
    <filter class="solr.RemoveDuplicatesTokenFilterFactory">
  </filter></filter></filter></tokenizer></analyzer>
  <analyzer type="query">
    <tokenizer class="solr.StandardTokenizerFactory">
    <filter class="solr.SynonymFilterFactory" expand="true" 
        ignorecase="true" synonyms="synonyms.txt">
    <filter class="solr.StopFilterFactory" ignorecase="true" words="stopwords.txt">
    <filter class="solr.StandardFilterFactory">
    <filter class="solr.RemoveDuplicatesTokenFilterFactory">
  </filter>
</filter></filter></filter></tokenizer></analyzer>
</fieldtype>

2) The spell field definition:

<field name="spell" type="spell" indexed="true" stored="false" multiValued="true" />

3) Populate the spell dictionary (field) with values from your content field(s):

<copyField source="content" dest="spell" />
<copyField source="description" dest="spell" />